In conventional burner apparatus, such as kerosene stoves, in which a wick is used and combustion is maintained by means of natural draft, there are possibilities that flames upwardly extend from the combustion cylinder of the apparatus to come out above the top panel thereof, which may result in a fire, in the following occasions:
a. when the wick is drawn out to its maximum height and left as it is; PA0 b. when wind blows to cause turbulence in combustion; and PA0 c. when the wick height is changed quickly from an ordinary height or relatively low height to the maximum height. In order to obviate the above-mentioned problem, a flame-shielding plate with the simplest shape is conventionally attached to the lower surface of the top panel, as shown in Japanese Utility Model Publication No. 14969/80.
An example of prior arts will be described hereinunder with reference to the accompanying drawings. In FIGS. 1 through 3, a reference numeral 1 denotes a box-shaped cabinet with its front side opened, while a numeral 2 denotes a lower-surface reflection plate partitioning the inside of the cabinet 1 into upper and lower parts. A fuel tank 3 arranged in the space of the lower part has cylindrical wick guides 4, 5 projected from the upper part thereof and a cylindrical wick 6 vertically movably fitted between the wick guides 4, 5. Moreover, the fuel tank 3 is provided with an operation knob 7 for vertically moving the wick 6. A reference numeral 8 denotes a known combustion cylinder comprising three cylindrical elements mounted on the wick guides 4, 5. The combustion cylinder 8 has a hemispherical radiating net 9 in the upper part thereof. A square plate-shaped top panel 10 formed above the combustion cylinder 8 has a plurality of exhaust holes 11 formed in its peripheral portion around the central portion thereof facing the combustion cylinder 8. In addition, a flame-shielding member 12 attached to the lower surface of the substantially central portion of the top panel 10 is in the shape of a cylinder and has the upper end thereof brought into contact with the lower surface of the top panel 10 without any space left. In this conventional arrangement, when the wick 6 is upwardly projected to its maximum height and left as it is, flames upwardly extending from the radiating net 9 once enter the flame-shielding member 12. However, since there is no space between the flame-shielding member 12 and the top panel 10, the flames collide against the top panel 10 to become energetic so as to scramble up the lower part of the flame-shielding member 12 as shown by an arrow in FIG. 3, so that the successive flames will not enter the flame-shielding member 12. Eventually, the flames undesirably come out through the exhaust holes 11 of the top panel 10, bringing about a very dangerous state. One way to resolve such a problem, is to increase the flame-shielding member 12 in height. In this case, however, such problems will arise in other respects that, for example, a catalyst cannot be installed above the combustion part since there is no sufficient space between the combustion part and the flame-shielding member 12. The above-mentioned phenomenon is remarkable, particularly when the stretch of flames is large and this condition is maintained in such a case where the height of the wick 6 is abruptly increased during combustion.